This invention generally relates to a catheter system for intravascular procedures such as percutaneous transluminal coronary angioplasty (PTCA) which has the capability of being readily exchanged for another catheter without the need for guidewire extensions and exchange wires.
In classic PTCA procedures, a guiding catheter having a preshaped distal tip is percutaneously introduced into the cardiovascular system of a patient and advanced therein until the preshaped distal tip thereof is disposed within the aorta adjacent the ostium of the desired coronary artery. The guiding catheter is twisted or torqued from the proximal end to turn the distal tip of the guiding catheter so that it can be guided into the coronary ostium. A dilatation catheter having a balloon on the distal end thereof and a guidewire slidably disposed within an inner lumen of the dilatation catheter are introduced into and advanced through the guiding catheter to the distal tip thereof. The distal tip of the guidewire is usually manually shaped (i.e. curved) by the physician or one of the attendants before the guidewire is introduced into the guiding catheter along with the dilatation catheter. The guidewire is first advanced out the distal tip of the guiding catheter, which is seated in the ostium of the patient's coronary artery, into the patient's coronary artery. A torque is applied to the proximal end of the guidewire, which extends out of the patient, to guide the curved or otherwise shaped distal end of the guidewire as the guidewire is advanced within the coronary anatomy until the shaped distal end of the guidewire enters the desired artery. The advancement of the guidewire within the selected artery continues until it crosses the lesion to be dilated. The dilatation catheter is then advanced out of the distal tip of the guiding catheter, over the previously advanced guidewire, until the balloon on the distal extremity of the dilatation catheter is properly positioned across the lesion. Once properly positioned, the flexible, relatively inelastic balloon is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g., 4-12 atmospheres) to dilate the stenosed region of the diseased artery. The balloon is then deflated so that the dilatation catheter can be removed from the dilated stenosis and blood flow can then be resumed therethrough.
Further details of guiding catheters, dilatation catheters, guidewires, and the like for angioplasty procedures can be found in U.S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 4,468,224 (Enzmann et al.); U.S. Pat. No. 4,516,972 (Samson); U.S. Pat. No. 4,438,622 (Samson et al.); U.S. Pat. No. 4,554,929 (Samson et al.); U.S. Pat. No. 4,582,185 (Samson); U.S. Pat. No. 4,616,652 (Simpson); U.S. Pat. No. 4,638,805 (Powell); U.S. Pat. No. 4,748,986 (Morrison et al.); U.S. Pat. No.4,898,577 (Badger et al.); and U.S. Pat. No. 4,748,982 (Horzewski et al.) which are hereby incorporated herein in their entirety by reference thereto.
Recently, the assignee of the present invention, Advanced Cardiovascular Systems, Inc., introduced into the market place an improved dilatation catheter which is described and claimed in copending application Ser. No. 550,801 (Yock), filed Jul. 9, 1990 and U.S. Pat. No. 4,748,982 (Horzewski et al.). This dilatation catheter has a short guidewire receiving sleeve or inner lumen extending through just the distal portion of the catheter. The sleeve extends proximally at least 10 cm, typically about 25 cm, from a first guidewire port in the distal end of the catheter to a second guidewire port in the side wall of the catheter. A slit is provided in the catheter wall which extends distally from the second guidewire port to a location proximal to the proximal end of the inflatable balloon. The structure of the catheter allows for the rapid exchange of the catheter without the need for an exchange wire or adding a guidewire extension to the proximal end of the guidewire.
The catheter design embodying the Yock and Horzewski et al. improvements has been widely praised by the medical profession and has been met with much success in the market place. Nonetheless, there are some inconveniences in its use. For example, the catheter shaft proximal to the proximal guidewire port contained both an inflation lumen and a stiffening member and in order to maintain a relatively low profile the inflation lumen frequently the catheter did not have a sufficiently large diameter for rapid inflation and deflation of the balloon. Additionally, it has been found that guidewires had a tendency to hang up on the notch in the catheter wall forming the proximal guidewire port, making withdrawal difficult.
What has been needed and heretofore unavailable is an intravascular catheter system which allows for the rapid exchange of a guidewire while providing for short inflation/deflation times and for a smooth insertion and withdrawal of a guidewire therefrom. The present invention satisfies these and other needs.